砷化合物致人表皮癌A431细胞的毒性及氧化应激和砷代谢研究

Cytotoxicity,oxidative stress and arsenic metabolism in human skin basal cell carcinoma cell(A431) induced by different speciations of arsenic

目的探讨不同砷化合物致人表皮癌细胞(A431)的细胞毒性及氧化应激和砷代谢的情况。方法培养的A431细胞分别暴露于0.05～50.0μmol/L一甲基亚胂酸(MMAⅢ),0.05～200.0μmol/L三氧化二砷(As2O3,As3+),0.5～500.0μmol/L砷酸氢二纳(As5+)和二甲基胂酸钠(DMAⅤ)24 h,应用四甲基偶氮唑盐(MTT)法测定细胞生存率;检测砷化物对丙二醛(MDA)含量、超氧化物歧化酶(SOD)活力的影响;以流式细胞仪检测细胞内活性氧(ROS);以原子荧光分析方法检测细胞内外不同形态砷含量。结果在一定剂量范围的MMAⅢ(≥5.0μmol/L)、As2O(3≥200.0μmol/L)、砷酸氢二钠(0.5,≥200.0μmol/L)和二甲基胂酸钠(500.0μmol/L)能够显著降低A431的细胞生存率(P<0.05,P<0.01),而在低剂量时,四种砷化物能显著促进A431细胞增殖(P<0.05,P<0.01)。与对照组相比,50.0μmol/L MMAⅢ组,50.0、250.0μmol/LAs2O3组,0.5μmol/L砷酸氢二钠组MDA含量均显著升高(P<0.05,P<0.01),而250.0μmol/L砷酸氢二钠和5.0～250.0μmol/L二甲基胂酸钠组MDA含量均显著降低(P<0.05,P<0.01)。与对照组相比,0.5、50.0μmol/L MMAⅢ组,5.0～250.0μmol/L砷酸氢二钠组和0.5～500.0μmol/L二甲基胂酸钠组的SOD活力显著升高(P<0.05,P<0.01)。细胞内活性氧含量依次为0.5μmol/L MMAⅢ>50.0μmol/L As2O3>100.0μmol/L砷酸氢二钠>100.0μmol/L二甲基胂酸钠。低剂量As2O3、砷酸氢二钠组细胞内砷甲基化率高于高剂量组,且As2O3组甲基化率高于砷酸氢二钠。结论在本实验条件下,不同砷化物在低剂量促进A431细胞增殖,高剂量抑制增殖,可能与A431细胞的氧化应激和砷代谢有关。

Objective To investigate the eytotoxieity and oxidative stress and arsenic metabolism induced by different speciations of arsenic in human skin basal carcinoma cell （A431）. Methods Cultured A431 cells were exposed to 0.05-50.0 μmol/L methylarsonous acid （MMAm）, 0.05-200.0μmol/L arsenic trioxide （As2O3, As^3＋）, 0.5-500.0 μmol/L disodium hydrogen arsenate（As5＋） or sodium dimethylarsonate（DMAv） for 24 h, respectively. MTT assay were used to evaluate the cell viability, the malondialdehyde （MDA） content and the activity of the superoxide dismutase （SOD） in HaCaT were detected respectively. The intraeellular reactive oxygen species （ROS） were detected with flow eytometry and the atomic fluorescence were used to analyze intracellular or extracellular levels of different speciations of arsenic. Results When the dose was in a certain range, MMA ^Ⅲ （≥0.5 μmol/L）, As203 （≥200.0 μmol/L）, disodium hydrogen arsenate （0.5, ≥200.0 μmol/L）and sodium dimethylarsonate （500.0 μmol/L） could all decrease the cell viability （P〈0.01 ,P〈0.05）, while four kinds of arsenides in lower dose could significantly promote the proliferation of A431 cell. Compared with those in the control group, 50.0 μmooL MMA ^Ⅲ ,50.0, 250.0 μmol/L As203, 0.5 μmol/L disodium hydrogen arsenate induced the significant increase of MDA contents （P〈0.01, P〈 0.05）, while 250.0 μmol/L disodium hydrogen arsenate and 5.0-250.0 μmol/L sodium dimethylarsonate could decrease MDA contents （P〈0.01, P〈0.05）. The SOD activity in 0.5, 50.0 μmol/L MMA^Ⅲ groups, 5.0-250.0 μmol/L disodium hydrogen arsenate and 0.5-500.0 μmol/L sodium dimethylarsonate groups were significantly higher than that in the control group （P〈 0.01, P〈0.05）. The intracellular ROS ranked as 0.5 μmol/L MMAm〉50.0 μmol/L As2O3〉100.0 μmol/L disodium hydrogen arsenate 〉100.0 μmol/L sodium dimethylarsonate. As for As2O3 and disodium hydrogen arsenate, the methylation ratios in low-dose groups were higher than the high-dose ones＇, and the ratios in As203 groups was higher than those in As5＋ groups. Conclusion Arsenides may inhibit A431 cells proliferation in higher exposure levels and promote proliferation in lower exposure levels, the mechanism probably relates to oxidative stress and arsenic metabolism in A431 cells induced by different speciations of arsenide with various concentrations.